Longitudinal web stretching machine



April 5, 1966 J. c. NASH 3,243,844

LONGI'IUDINAL WEB STRETGHING MACHINE Filed April 28, 1964 7 Sheets-Sheet1 INVENTOR JOHN CRANDON NASH MM 5 M 36mm AT TOR N EY April 1966 J. c.NASH 3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 '7 Sheets-Sheet2 INVENTOR.

\ JOHN CRANDON NASH ATTORNEY April 5, 1966 Filed April 28, 1964LONGITUDINAL WEB STRETGHING MACHINE 7 Sheets-Sheet 3 Q Q Ma gg m \QI QINVENTOR. \Q Q JOHN CRANDON NASH ATTOR N EY April 1966 J. c. NASH3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 7 Sheets-Sheet4 ATTORNEY April 1966 J. c. NASH} 3,243,844

LONGITUDINAL WEB STRE'I'GHING MACHINE Filed April 28, 1964 7Sheets-Sheet 5 I 4 ll \n INVENTOR- F168 JOHN CRANDON NASH m Mun ATTORNEY7 Sheets-Sheet 6 .iwmymuw ATTO R N EY April 5, 1966 J. c. NASHLONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 JOHN CRANDONNASH Jung FIG. IO

FIGIZ April 5, 1966 J. c. NASH 3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 7 Sheets-Sheet7 JOHN CRANDON NASH B1 ATTORNEY United States Patent 3,243,844LONGIIUDINAL WEB STRETCHING MACHENE John Crandon Nash, Providence,12.1., assignor to Marshall and Williams Corporation, Providence, ELL, acorporation of Rhode Island Filed Apr. 28, 1964, Ser. No. 363,249

17 Claims. (Cl. 18-1) The present application is a continuation-impartof United States patent application Serial No. 230,491 filed October 15,1962, for a Longitudinal Web Stretching Machine, now United StatesPatent No. 3,208,100 dated September 28, 19 65.

This invention relates to apparatus for stretching webs and films andmore particularly it relates to a machine for longitudinally stretchingplastic film in a plastic or heat softened state to increase the filmlength and reduce the film thickness.

An object of the present invention is to provide a machine withapparatus for heating a continuous web of plastic film to apredetermined temperature at the marginal line of stretch tension and toprovide draw rolls for longitudinally stretching the continuous web asit passes from feed rolls to draw rolls.

Another object of the present invention is to provide a machine, forlongitudinally stretching a running web of plastic film, between a setof feed rolls and a set of draw rolls. The draw rolls being rotated atvarying relative speeds, in relation to the feed rolls at varyingselected relative distances from the feed rolls. The surfacetemperatures varying on the set of feed rolls and the draw rolls.

Other objects of the present invention will become apparent in part andbe pointed out in part in the following specification and claims.

The present application is an improvement over my co-pending applicationSerial No. 230,491 filed October 15, 1962,'for a. Longitudinal NobStretching Machine.

With the advent of increased use of plastic film for a variety ofarticles there has developed a need to longitudinally stretch a web ofplastic film to provide a web of desired width and thickness. Effortshave been made to initially manufacture a web of desired width andthickness. Such efforts have not been commercially successful. It hasbeen found that the successful stretching of a plastic web requires fourphysical conditions:

(1) The heating of the plastic web or film to a proper degree to heatsoften or plastercise the film to a proper consisting;

(2) A predetermined stretch ratio of the film must be provided for;

( 3) A predetermined stretch rate must be provided for;

(4) The heat softened film must be set after stretching.

These four conditions are provided for in the present longitudinal webstretching machine. (1) The film to be stretched is heated to a properdegree by a set of feed rolls. A heating lamp is provided to addadditional heat when necessary at the marginal line of initialstretching. (2) The stretch ratio of the plastic film is provided for bythe difference in linear speeds between the feed rolls and the drawrolls. (3) The stretch rate of the plastic film is determined by thelinear distance between the two points of tangency on adjacent drawrolls of the two separate sets of rolls, namely feed roll and draw roll.This linear distance is variable through the adjustment feature ofpivoting the draw rolls toward and away from the feed rolls. (4) Theplastercised stretched film is set by the surface temperature of thesecond set of draw rolls. In addition, the adjustable featurefacilitates the initial threading of the web around both sets of drawrolls.

Referring to the drawings in which similar characters of referenceindicate corresponding parts:

FIGURE 1 is a perspective view of the new and im proved longitudinal webstretching machine as viewed from the front left corner of the machine.

FIGURE 2 is a front elevational view of the machine.

FIGURE 3 is a plan view of the machine.

FIGURE 4 is a vertical cross sectional view through the machine, takenon line 44 of FIGURE 2, looking in the direction of the arrows.

FIGURE 5 is a view similar to FIGURE 4 showing the set of draw rollspivoted the maximum distance away from the cooperating set of feedrolls.

FIGURE 6 is a left side elevational view as viewed in FIGURE 1.

FIGURE 7 is a vertical cross sectional view, partially broken away,taken along line 77 of FIGURE 6, showing the construction of the gagecontrol mechanism.

FIGURE 8 is a cross sectional view taken on line 8-8 of FIG. 7.

FIGURE 9 is a fragmentary cross sectional view, taken on line 99 ofFIGURE 6.

FIGURE 10 is a side elevational view of a detail showing of a side frameof the machine.

FIGURE 11 is a side elevational view of a detail showing of a pivotalarm.

FIGURE 12 is a fragmentary schematic perspective view taken generallyupon line 4-4 in FIGURE 2, looking in the direction of the arrows fromthe rear left corner of the machine.

FIGURE 13 is a vertical cross sectional view through the machine takenalong line 13-13 of FIG. 2, looking in the direction of the arrows.

FIGURE 14 is a fragmentary schematic perspective view, illustrating theconstruction for adjusting the auxiliary heating means.

According to the invention the new and improved longitudinal webstretching machine consists of a frame having left side vertical wall 11and an opposite and parallel right side vertical wall 12. Spacingbrackets 15, 16 and 17 are welded on opposite ends, respectivelypto leftand right side vertical Walls 11 and 12. A plate 18 may be welded tospacing brackets 15 and 1-6.

An angle iron 19 may be'welded to right side vertical wall 12 and tospacing brackets 15, 16. A similar angle iron 20 may be welded to leftside vertical wall 11 and to spacing brackets 15, 16.

FIGURE 10 represents in detail, right side vertical wall 12, providedwith drive shaft bearing supports 21, 2 2; bearing support 23 slotted at24, hearing support 25 slotted at 26 and a notch consisting of a bottom27, a backstop 23 and a front stop 29. Left side vertical wall 11 isidentical in construction to right side vertical wall 12. When referenceis made hereinafter'to left side vertical wall 11, the sufiix A will beadded to the reference numerals appearing in FIGURE 10.

FIGURE 11 represents in detail a right side pivoted arm 31) providedwith a bearing support 31, a bearing support 32 slotted at 33, and abearing support 34 slotted at 35. Left side pivoted arm 36 is identicalin construction to right side pivoted arm 31 When reference is madehereinafter to left side pivoted arm 36, the suffix A will be added tothe reference numerals appearing in FIGURE 11.

Bearings 42, 43 are fixed in bearing supports 21, 22, respectively, inright side vertical Wall 12. Similarly, hearings 42A, 43A are fixed inbearing supports 21A, 22A, respectively, in left side vertical *wall11'. Drive shafts 44, 45 are rotatively mounted on opposite ends,respectively, in bearings 42, 42A and 43, 43A.

A suitable bearing (not shown) is fixed in bearing support 31.Similarly, a further bearing (not shown) is Patented Apr. 5, 1966 fixedin bearing support 31A. Right side pivoted arm 39 is pivotally mountedupon drive shaft 44 through the bearing in bearing support 31. Left sidepivoted arm 36 is pivotally mounted upon drive shaft 44 through abearing in bearing support 31A.

A stop rod 47 is fixed on opposite ends, respectively, to left and rightside pivoted arms 36, 30 and is adapted to abut back stop 23 and frontstop 29. In this manner right and left side pivoted arms 30, 36 arelimited in their pivotal movement.

A double acting air cylinder 50, Model PDSCB3CR 50, five inch stroke,three inch bore, manufactured by Bellows Valvair Company, Akron, Ohio,is provided to pivot arms 30, 36.

A bracket 48 is fixed on opposite ends, respectively, to right and leftside pivoted arms 30, 36. A power unit, in the form of an air cylinder50 is fastened on one end to spacing bracket 15 and on the other end tobracket 48 to pivotally actuate and control the pivotal movement ofright and left side pivoted ams 30, 36. A pair of spacer bars 49 and 51(see FIGURES 1, 4, 5 and 12) are connected at their opposite ends toarms 30 and 36 and serve to connect and provide rigidity to the upperend of these pivot arms.

A set of feed rolls and a set of draw rolls are provided for stretchingthe web. The stretching operation takes place between adjacent rolls ofthe opposite sets of rolls.

The sets of draw rolls may constitute one roll in each set because thestretch ratio and stretch rate are determined by the relationshipbetween these two rolls. However, for purposes of supplying sufiicientheat to the web and to prevent slippage of the web on the draw rolls,two, three or more rolls may constitute a set of draw rolls. Forpurposes of illustration two rolls are shown as constituting a set ofdraw rolls.

Four calendar rolls, here referenced as 37, 38, 40 and 41 are providedfor accommodating the web to be processed on the machine. Each of thesedraw rolls preferably takes the form of the draw roll shown anddescribed in United States Patent No. 2,498,662, or in United StatesPatent No. 1,651,502 or in United States Patent No. 3,120,867 datedFebruary 11, 1964, by John Crandon Nash. Briefly, these rolls 37, 38, 40and 41 in clude internal compartments or chambers indicated at 37A, 38A,40A, and 41A, respectively which are adapted to communicate with asource of fluid. This fluid, which is heated to a predeterminedtemperature, acts to heat the surface of each of the rolls therebyserving to heat the web passing around the rolls. Obviously, while therolls are referred to as being heated, they or any of them, could becooled or otherwise surface temperature controlled to the end that adesired temperature environment for a web being handled on the machinecan be achieved.

To consider, now, the particular mounting of the calendar rolls, it willbe observed from the drawing (FIGS. 4 and 5, for example), that theserolls are actually constituted .as two individual sets. Thus, a set ofdraw rolls 37, 38 is seen to be supported between the pivoted arms 30,36. Draw roll 37 is rotatably supported at its left hand side (see FIGS.1 and 9) on a stub shaft 68, which said shaft may be formed integrallywith this draw roll to extend therefrom. As best seen in FIG. 9 stubshaft 60 projects through and rotates on bearing 61 seated in bearingsupport 34A. A drive gear 69 is connected to stub shaft 60 by engagementwith a key 70. This gear 69 being disposed on the outer end of shaft 69.The opposite end of draw roll 37 is provided with a projecting hollowshaft 72 which is rotatable in a bearing 74 carried within bearingsupport 34 (see FIGS. 3 and 11). The outer end of hollow shaft 72 has arotary fluid coupling 76 mounted thereon to thereby provide a connectionto a suitable source of fluid. Said fluid is permitted to flow throughhollow shaft 72 and into the compartment 37A within draw roll 37 tothereby heat this roll as in accordance with the structure of thepatents and patent application earlier cited.

In like manner as just described in connection with calendar or drawroll 37, the companion draw roll 38 of this set is supported at its lefthand end on a stub shaft 78 carried in suitable hearings in left sidepivoted arm 36. The outer end of shaft 78, which projects beyond theoutside of arm 36 has a sprocket 80 thereon and keyed thereto so thatsaid sprocket 80 may drive shaft 78. A gear 82 is also affixed tightlyon shaft 78 in order that this gear will rotate positively with saidshaft 78. The opposite end of draw roll 38 is supported on a hollowshaft 84 rotatable in a suitable bearing 86 carried in bearing support32 of right side pivoted arm 30. The outer end of hollow shaft 84 has afluid coupling 88 attached thereto and arranged to receive a fluid froma suitable source whereby this fluid may be conducted through hollowshaft 84 and into compartment 38A of draw roll 38. In this fashion drawroll 38 is heated.

Advantageously, a guide roll and companion nip roll or pinch roll areprovided to operate cooperatively with movement of a web being carriedaround the diameter of draw rolls 37, 38. Accordingly, a first shaft 94is supported for rotation in suitable bearings carried in bearingsupports projecting rearwardly from the rear edges of pivot arms 30, 36.One of these bearings is shown at 95 in FIG. 6, and in this same viewthe bearing support therefore may be seen at 96 carried on pivot arm 36.It will be appreciated that an identical bearing for this shaft 94 willbe provided at in bearing support 96A in opposite pivot arm 30 (see FIG.4). A guide roll 97 is secured onto shaft 94 as by a press fit to berotatable therewith in response to frictional contact of a web beingdrawn thereacross. As seen in FIGS, 4, 5 and 12 guide roll 97 issituated rearwardly of draw rolls 37, 38 and approximately midwaybetween the respective axes of these two draw rolls. Thus, guide roll 97serves to guide the web partially around draw roll 37 (see FIGS. 4 and5) and further serves to keep the web flat and wrinkle free as the webadvances.

A companion pinch roll 98 is provided to operate in conjunction withrotation of draw roll 38. To this end a shaft 99 is rotatably mounted atits opposite ends in the outer ends of a pair of bell crank levers 100and 100A; one of which is seen at 106 in FIGS. 4 and 5 and the oppositeone of which is shown at 100A in FIG. 13.

Lever 108 is rockably supported upon a post 101 projecting outwardlyfrom the interior wall of right side piv oted arm 30. Similarly, lever1418A is rockably supported upon a post 101A fastened in and projectingfrom the interior wall of left side pivoted arm 36. A hydraulic cylinder102 is connected to a leg 104 which, in turn, is fastened to frame bar48 at the right hand side of the machine. A like arrangement for shaft99 consisting of hydraulic cylinder 102A connected to a leg 104A (seeFIGURE 13) provided for the distal end of shaft 99, i.e., the shaft endadjacent left side pivot arm 36 (see FIG. 13).

Pinch roll 98 is formed as an elongated cylinder, preferably of aheat-resistant frictional material press-fitted onto shaft 99 forrotation therewith. Upon actuation by hydraulic cylinder 102, pinch roll98 can be rocked about post 101 from its inoperative position as shownin FIG. 5 to its operative position as seen in FIG. 4 wherein it pressesagainst draw roll 38. Thus, pinch roll 98 can rotate by frictionalcontact with draw roll 38 to prevent the web from slipping on the drawroll and to keep the web flat.

Gear 82 has been stated as afiixed to shaft 78 for rotation therewith.This gear 82, which forms part of a gear train, acts as the driver forrotating draw roll 37 in con-- cert with rotation of draw roll 38. Thus,with reference: to FIGS. 1, 2 and 6 a pair of gears 39 and 90 aremountedv for rotation on the outer ends of stub shafts 91 and 92;respectively, said stub shafts 91, 92 being emhfiddfid. in;

the wall of pivot arm 36. Gears 89 and 90 are mounted so as to enmeshwith each other. Moreover, gear 89 intermeshes with gear 69 on shaft 60.In a similar manner gear 98 intermeshes with gear 82 on shaft 78.

To the end that simultaneous, positive movement may be imparted to drawrolls 37 and 38, a relatively small diameter driver sprocket 103 issecured to drive shaft 44 for rotation therewith. An endless chain 118passes about sprocket 108 and is engaged with sprocket 80. Thus, asdrive shaft 44 is operated its power is transmitted by chain 110 tosprocket 88 whereupon draw roll 38 and its companion roll 37 arerotated. An idler sprocket 112 is rotatably mounted on a stub shaft 114projecting outwardly from an arm 116. This arm 116 is adjustable on apost 118 extending out from the side of pivoted arm 36. Idler sprocket112 engages chain 110 between sprockets 80 and 108 and by suitablepositioning of arm 116, this idler sprocket 112 is operable to adjusttension in chain 110.

Rolls 40 and 41 constitute a set of feed rolls operable cooperativelywith the earlier described set of draw rolls, i.e., draw rolls 37, 38,in order to achieve controlled stretching of a continuous web. This setof feed rolls are fixed in position for rotation as opposed to drawrolls 37, 38 which are pivotable about a horizontal axis.

To consider firstly the mounting for feed roll 40, this roll issupported at its left-hand end on a stub shaft 120 (see FIG. 1) whichmay be formed integrally with the roll, the stub shaft projecting fromthe roll 40 and extending through the side 11 of the machine. A suitablebearing, not illustrated, is provided in the side wall 11 from rotationof stub shaft 120. The outer end of shaft 120 has a gear 122 securedthereon as by key means (not shown). The opposite end of feed roll 49 isprovided with a centerless shaft 124 (see FIGURE 3) which passes throughand is rotatable on a bearing 126 pressed into the side 12 of themachine. A-fluid coupling 128 is attached to the outer end of centerlessshaft 124 and provides a means for introduction of a fluid into thechamber 40A of calendar or feed roll 40.

The mounting for feed roll 41 is generally similar to that justdescribed for feed roll 40. Feed roll 41 is carried at its left hand endon a stub shaft 130 (see FIGURES l and 2) formed integrally with the endflange of the draw roll. wall 11, through bearing 131, and has asprocket 132 aflixed thereon as by being keyed thereto. A gear 134 isalso keyed to shaft 130, this gear lying intermediate sprocket 132 andthe outside of wall 11. The opposite end of feed roll 41 has acenterless shaft 136 connected thereon and extending outwardly beyondwall 12, passing through a bearing 138 in said wall 12. The outer end ofcenterless shaft 136 has a fluid coupling 140. In accordance with thepresent invention temperature controlling fluid may be admitted throughfluid coupling 140, passing through centerless shaft 136 and intochamber 41A to thereby adjust the surface temperature of feed roll 41.

As in the case of the set of draw rolls 37, 38, earlier described, thefeed rolls 40, 41 are provided with a cooperating guide roll and pinchroll. To this end a guide roll 142 is supported on a shaft 144. Theopposite ends of shaft 144 are journalled in suitable bearings in. thewalls 11 and 12 of the machine. The bearing 146 for shaft 144 in wall 11is seen in FIG. 1. As is readily apparent in FIGS. 4 and 5 guide roll142 acts to rotate by frictional contact with the web and to direct theweb into the machine in a flat condition whereby the web is guided tofeed roll 41.

A second or auixliary guide roller 148 is preferably arrangeddownstream, or beyond guide roller 142 to thereby assist in moving theweb to feed roll 41. This further guide roller 148 is carried on anelongated shaft 158, the opposite ends of said shaft being carried insuitable bearings 152 (FIG. 1) in opposite side walls 11, 12 of the Stubshaft 130 projects beyond the outer side of machine. As is readilyevident in FIGS. 4 and 5 auxiliary guide roller 148 receives the webfrom guide roller 142 for delivery to feed roll 41. As with guide roll142, guide roll 148 is freely rotatable under the frictional drag of theweb being drawn thereover.

A pinch roll 154 is supported at the forward end of the machine on anelongated shaft 156. In turn, the opposite ends of shaft 156 arerotatably supported in the inner ends of a pair of hell crank levers158, 158A, the lever 158 adjacent the right side of the machine beingillustrated in FIGS. 4 and 5. The bell crank lever 158A, locatedadjacent the left side of the machine is shown in FIG. 13. Bell cranklever 158 is rockable on a stud 160 embedded in right side vertical wall12 of the machine. Bell crank lever 158A is rockable on a stud 160Afastened in left side vertical wall 11. The outer or lower end of eachbell crank lever 158, 158A has a rod 162, 162A, respectively, connectedtherewith. The distal end of each rod 162, 162A is connected with arespective hydraulic cylinder 164, 164A, for controlling the movement ofpinch roll 154. By the actuation of hydraulic cylinders 164, 164A, pinchroll 154 maybe rocked against the surface of draw roll 41 and,similarly, may be rocked away from engagement therewith. The inner endof each hydraulic cylinder 164, 164A is suitably connected to the walls12, 11, respectively, of the machine by brackets 166, 166A and pivotpins 167, 167A, respectively. The cylinders are therefore free to rockin conjunction with their operation of pinch roll 154. i

In order that the web may be pressed tightly onto the surface of a feedroll 40 a further pinch roll 174] is supported in opposite bell cranklevers connected in walls 11, 12 of the machine much in the same manneras just described with pinch roll 154. Pinch roll 170 is mounted forrotation on a shaft 172, the opposite ends of this shaft being supportedfor rotation is one end of a pair of hell crank levers 176, 176A. InFIGS. 4 and 5 there is shown the bell crank lever 176 adjacent wall 12for mounting shaft 172 and in FIG. 13 bell crank 176A is shown adjacentwall 11 for supporting the opposite end of shaft 172. Bell crank levers176, 176A are supported medially on Posts 178, 178A for rockablemovement thereabout. Posts 178 and 178A are fastened, respectively, inright and left side vertical walls 12 and 11. The end of the levers 176,176A opposite from shaft 172 are connected to rods 180, 180A,respectively, which joins with respective hydraulic cylinders 182, 182A.Upon actuation of hydraulic cylinders 182, 182A, pinch roll 170' may berocked against the periphery of feed roll 40 to press the webthereagai-nst and may also be rocked away from this feed roll as whenthe web is being initially wrapped about the roll. The lower ends ofhydraulic cylinders 182, 182A are pinned at 183, 183A, to oppositebrackets 184, 184A which are, in turn fastened to right and left sidevertical walls 12, 11, respectively.

The drive for feed rolls 40, 41 is received from a sprocket 186 affixedfor rotation on the outer end of drive shaft 45. As best seen in FIG. 6an endless chain 188 is passed around sprocket 186 and sprocket 132 toconnect these two components together for operation. A pair of idlergears 19%), 192 are supported on respective stub shafts 194,196'r'nounted in and projecting outwardly from the left side verticalwall 11 of the machine. Gears 190 and 192 are enmeshed with each other.Further gear 191 is enmeshed with gear 122 on stub shaft 120 while gear192 is enmeshed with gear 134 on stub shaft 136. In consequence thereofpower is transmitted from drive shaft 45 through chain 188 to rotatefeed rolls 4% 41.

A small idler sprocket 198 is positioned in the path of chain 188-fortensioning the chain. Idler sprocket 198 is held for rotation on a shortshaft 200 located at one end of an arm 282. The opposite end of arm 202is clamped onto a post 204 fixed in wall 11, so that the arm may berocked thereabout to a suitable location after which the arm 202 isclamped to the post by bolt 206. In this way idler gear can be rockedinto the path of chain 188 to be rotated thereby and to tension thechain.

The present invention includes (see FIGURES 1, 2, 3, 4, 5, 6, 7, 12 and13) an advantageous arrangement permitting the set of draw roll 37, 38to be micrometer ad justed relative to the set of feed rolls 40, 41 sothat the stretch distance may be accurately determined.

To this end a pair of oppositely disposed square shaped brackets 210 and212 are provided at the front of the machine. Square shaped bracket 210is provided with a square shaped hollow bore 212C and a forwardlyprojecting arm 212D having a pair of ears 212E, 212F. A U-shaped bracket225 is fastened to left side vertical wall 11 as by means of welding.Trunnions 237 and 238 integrally formed in square shaped bracket 210 arepivotally mounted in U-shaped bracket 225 in bearings provided for thatpurpose. Square shaped bracket 212 is similarly constructed and isprovided with a pair of cars 2126 and 2121-1. A U-shaped bracket 227 isfastened to right side vertical wall 12 as by means of welding. Saidcars 212E, F, G, H, have aligned bores therethrough to receive oppositeend sections of a cross-shaft 214. Advantageously, cross-shaft 214 has apair of universal joints therein at 215 and 216 to insure alignment andthus free rotational movement of this shaft. A bevel gear 218 is securedonto the diameter of cross-shaft 214 within the confines of bracket 210.In like manner, a further bevel gear 220 is affixed on the outer sectionof cross-shaft 214 within the channel of bracket 212. A hand-wheel 222having appropriate graduations marked on the periphery thereof is keyedonto the outer end of cross-shaft 214 adjacent wall 11. An indicator 223(see FIGURE 6) is attached to a bracket 225 fastened to wall 11 toprovide a convenient pointing means cooperable with movement ofhand-wheel 222.

The square shaped hollow bores 212C accommodate threaded shafts 228,230. Thus square shaped brackets 210 and 212 have shafts 228, 230,respectively, projecting therethrough to accommodate bevel gears 232,234 and fastened thereon, respectively. Bevel gear 232 meshes with bevelgear 218. Bevel gear 234 meshes with bevel gear 220. It will, thus, beevident that rotation of crossshaft 214, as by hand wheel 222, will beeffective to rotate shafts 228 and 230.

In FIG. 7 there is depicted the details of one of the square shapedbrackets 210 or 212 and its companion shaft 228 or 239. It will beunderstood that since the construction of each member and its relatedcomponents is identicaL'reference can be directed to the features of thesingle structure of FIG. 7 to describe both square shaped bracket 210,212 related components. Square shaped hollow bore 212C accommodatesopposite aligned plain bearings 239, 240 therein as by a press fit.Shaft 228 is rotatable on bearings 239, 240. The outer half,approximately, of shaft 228 is threaded as indicated at 242, and issurrounded by a relatively large diameter tube 241, said tube beingconnected at one of its ends to square shaped bracket 210. The threadedportion of shaft 228 serves to receive a large nut 244 in threadedengagement therewith. Nut 244 is fitted within and is slidablelongitudinally of tube 241. A fiber collar 244C is slidably mountedwithin tube 241 and normally abuts nut 244. The rearward end of a hollowrow 246 is pinned at 247 to yoke 248. Said yoke 248, in turn, projectsrearwardly and is connected to the side of pivot arm 36 by a crosspin251 It will, therefore, be seen that rotation of crossshaft 214 willimpart simultaneous rotation to shafts 228 r and 239. In consequencethereof, rotation of shafts 228,

230 causes nuts 244 engaged with these shafts to move longitudinallythereof.

Actuation of air cylinder 50 will move pivot arms 30, 36 about shaft 44and thereby move arm 36, for example, and yoke 248 attached to hollowrod 246. In this manner hollow rod 246 is slidable Within tube 241 sothat the end of tube 241 will rest against fiber washer 244C. Ro tationof hand wheel 222 will rotate shaft 228 through cross-shaft 214 andbevel gears 218, 232 and thereby position nut 244 in selected positionwithin tube 241. Air cylinder 50 through hollow rod 246 will force fibercollar 244C against nut 244 to position pivoted arms 30, 36 in selectedposition as dictated by the position of nut 244. Consequently, drawrolls 37, 38 are moved as pivot arms 30, 36 are rocked until the precisedistance is established between the draw roll 38 and feed roll 40. Drawrolls 37, 38 constitute a set of feed rolls, and draw rolls 40, 41,constitute a set of feed rolls.

The distance, known as the stretching zone, determines the rate at whichthe web will be stretched. Thus, the apparatus of the present inventionaffords a quick and accurate means for establishing the stretchdistance, which in turn, contributes to high quality production from themachine.

A calibrated scale 350 (see FIGURES 6 and 7) is fastened to yoke 248 bymeans of rivets 351. An indicating bar 352 constructed so as to allowcalibrated scale 350 to slide therethrough, is fastened to tube 241 asby means of welding. In this manner, the pivotal movement of arms 30, 36as dictated by air cylinder 50, may be calibrated.

The power means for the present invention (see FIG- URES 2 and 3)includes an electric motor 250 bolted to a base 251. Motor 250 isprovided with a power shaft 252 onto which is operatively connected to apulley 254. A variable speed mechanism 256 is also bolted onto base 251and is connected to motor 250 through a driving belt 258, this beltbeing wrapped about pulley 254 and passing around a pulley 260 on thevariable speed mechanism 256. Motor 250 is a variable speed motor of anyconventional type or a conventional electric motor with a variable speeddrive having control means which varies the rotational speed of shaft252.

Variable speed mechanism 256 may be a positively variable speedmechanism such as that disclosed in United States patent applicationSerial No. 197,016 filed May 23, 1962, by John Crandon Nash or it may beany other variable speed transmission. As illustrated, variable speedmechanism 256 is provided with a speed control device or variator 262which is disclosed in United States Patent 2,469,653 dated May 10, 1949.Variator 262 is provided with a shaft 264 operably connected with apulley 266 and a shaft 267 having a pulley 268. Variable speed mechanism256 is provided with a shaft 269 having a pulley 270. A belt 272operatively connects pulleys 268 and 270. A further belt 274 operativelyconnects pulley 260 with pulley 266. Variable speed mechanism is alsoprovided with a shaft 276 and two output shafts 278, 280. Output shaft278 is connected through flexible coupling 282 with drive shaft 44.Likewise, shaft 280 is connected by means of flexible coupling 284 withdrive shaft 45.

Shaft 264 of variator 262 is rotated at the preselected speed of shaft276. The variator 262 will operate to change the relative speed of shaft267 so that this shaft will rotate at a speed relative to that of shaft264. This adjustment may be achieved by manual means not hereinillustrated but which are common to variable speed control devices ofthe type herein contemplated. In this manner feed rolls 40, 41, whichserve primarily to heat the web, are driven at preferably a slower speedthan draw rolls 37, 38. To this end feed rolls 40, 41 are rotated fromdrive shaft 45 which is connected with output shaft 230. This outputshaft 280 is rotated at a reduced speed relative to the speed of outputshaft 278 through variator 262 in order that fed rolls 4%, 41 may rotateat a similar reduced speed. In contrast thereto, draw rolls 37, 38 whichserve primarily to stretch the web, are rotated at a speed somewhatfaster than feed rolls 40, 41 since the drive shaft 278 for these feedrolls is rotating at a relative fast speed as contrasted with that ofoutput shaft 280. The difference in speed between the feed rolls 37, 38as compared to that of draw rolls 40, 41 varies the pull or tension inthe web stretched between them, thus providing the stretch ratio for theweb. This pull or tension is also varied by the variation in stretchdistance, that is to say, the distance as established between the pointsof tangency where the web contacts roll 38 and feed roll 40. Thisdistance or dimension provides the stretch ratio for the web. Moreover,this distance is set or established by pivoting arms 30, 36 to therebygenerate or rock draw rolls 38, 37 about the horizontal axis of shaft 44and, thus, achieve movement of these draw rolls relative to feed rolls40, 41.

The present invention includes auxiliary heating means in the event itis necessary or desirable to introduce a momentary application of heatto the web as stretch as applied. To this end a radiant heater 290 ofany conventional type as, for example, the radiant heater manufacturedby the Edwin LWiegand Company, Pittsburgh, Pennsylvania, catalog numberRADD-3224, Chromalox Radiant Heater may be utilized. The heater 290 isso positioned as to heat the web at the line of tangency of feed roll 40where the web is delivered therefrom toward draw roll 38. It is, ofcourse, at this point that stretch is first applied to the web. Heater290 is of sufiicient length to be coterminous with'fee-d roll 40. Saidheater is supported by a pair of arms, one of which is shown at 292 (seeFIGS. 4 and 5). A like arm is located at the opposite side of themachine for holding the opposite end of the heater 290. bracket 294 isfastened to wall 12 of the machine and a like bracket (not shown) isconnected to wall 11. Arm 292 is pivotally connected to bracket 294 bystud 296 Thus, the heater 290 may be pivoted to the desired distancerelative to the web running ofi feed roll 40. V

The operation of the present invention is thought to be moreor lessapparent from the foregoing description. However, it will servetosummarize the operation of the machine in its operation of stretching aweb of plastic film. As best seen in FIGS. 4 and 5 the web W is drawnfrom a suitable supply source and directed over guide roller 142 andover secondary guide roller 148. Since these rollers are freelyrotatable the web may be drawn around the periphery of feed roll 41,pinch roller 154, at this time, being separatedfrom feed roll 41 toadmit the web W therebetween. As seen in FIGS. 4 and 5 the web W iswrapped part way around the periphery of feed roll 41, passingtherearound in a clockwise direction, after which the web W is directedupwardly and counterclockwise around feed roll 40. The web W then spansa zone z which is the stretch distance for the film and, as earlierstated,'is the distance feed roll 38 is set apart from draw roll'40. Theweb then passes clockwise partially around draw roll 38 whereafter theweb is directed upwardly passing around draw roll 37 in acounterclockwise direction. The web W is fed off draw roll 37 to asuitable take-up.

The stretch distance or zone z is established to conform to the rate ofstretch desired for the web W. This distance is set by rotatinghandwheel 222 which, in turn, rotates cross-shaft 214 to turn shafts228, 230 as preyiously explained for shaft 228. In consequence thereof,draw rolls 37, 38 are positioned relative to a feed rolls 40, 41. Heatedfluid is introduced into chambers 40A, 41A through fluid couplings 128,140, respectively, and centerless shafts 124, 136, respectively. In thismanner heat is transferred to the surface of a feed rolls 40, 41 to heatand thereby heat soften or plasticise the plastic web W. The particulartemperature of the fluid to be introduced to the chambers 37A, 38A ofrespective draw rolls 37, 38 will, of course, depend on the treatment tobe given the web. The fluid may be a coolant to cold set the stretch inthe web or, on the other hand, may be heated fluid to heat set the web.

Variator 2 6 2 is adjusted to establish a relative rate of 'rotation'between feed rolls 37, 38 as compared with draw rolls 40, 41. Thedifference in speed will determine the it) stretch ratio and, for thispurpose, draw rolls 37, 38 will, obviously, be driven somewhat fasterthan feed rolls 40, 41.

With the machine so arranged as described above, hydraulic cylinders164, 132 and 102 areactuated to urge their respective nip or pinch rolls154, and 98 against the associated rolls. These pinch rolls act toprevent the web W from slipping as great tension is placed thereonduring longitudinal stretching. The pinch rolls, together with thevarious guide rollers, further, servesto keep the web flat and to removewrinkles which might otherwise be presented in the web duringprocessing. Thus, the web may be moved through the machine and belongitudinally stretched. Additionally, the web may be further heated byradiant heater 290 if desired.

FIGURE 14 illustrates a bracket construction which provides adjustablemeans for positioning radiant heater 2% toward and away from feed roll40 in the stretching zone of the web.

Right side vertical wall 12 provided with bearing support 23 is providedwith a plate 300. Bolts 301 secure plate 300 to wall 12 above thebearing support 23 for feed roll 40. Similarly, plate 302 is fastened toleft side vertical wall 11. Bracket 294C is fastened to plate 300 bymeans of bolts 303. Similarly, bracket 294D is fastened to plate 302. Anarm 292C provided with an elongated slot 304 is pivotally connected tobracket 294C by means of a stud 296C. A wing nut 305 rotatively mountedupon stud 296C frictionally holds arm 292C in selected or adjustedposition in relation to bracket 294C. Similarly, arm 292D provided withelongated slot 304A is piyotally connected to bracket 294D by means ofstud 296D. Wing nut 305A rotatively mounted upon stud 296D frictionallyholds arm 292Dv in adjusted position in relation to bracket 294D.

Radiant heater 29.0 is provided on opposite ends with brackets 307 and307A. A stud 310 fixed to bracket 307 is slidably mounted in elongatedslot 304. A wing nut 311 rotatively mounted upon stud 310 frictionallyholds bracket 307 in selected or adjusted position in elongated slot304. Similarly, a stud 310A fixed to bracket 307A is slidably mounted inelongated slot 304A. A wing nut 311A rotatively mounted upon stud 310Africtionally holds bracket 307A in adjusted position in elongated sl ot304A.

In this manner radiant heater 290 is adjustable in parallel elongatedslots 304, 304A so as to be movable within the stretch zone and towardand away from feed roll 40. These two separate adjustments of theheater, toward and away from feed roll 40 in an up and down directionthrough studs 296C and 296D and toward and away from feed roll 40through the elongated slpts allows for a positioning of the auxiliaryheat in a position complimentary to the surface heat of feed roll 40.

The length of time a plastic web is held in a heat softened orplastercized condition is critical to the proper stretching of theplastic web. Where auxiliary heat is necessary to heat soften a plasticweb, it must be applied at a critical location in relation to theprincipal heating means, such as feed roll 40.

' When two or more feed rolls 40 and 41 are used to heat and guide theweb to the second set of draw rolls 37, 38, it has been foundadvantageous with certain types of plastic film to provide the top rollof the set, in this instance feed roll 40, with a slightly greatersurface speed in this instance feed roll 41. This increased surfacespeed provides a take up of the web when the nature of Web material issuch as to cause the web material to expand when subjected to the heatof the roll 41. The take up eliminates wrinkles in the web due to theheat expansion of the web material. Some web materials shrink whensubjected to heat. The occasion may then arise when the surface speedmay be reduced.

Feed roll 40 may be provided with an increase surface speed in a numberof ways. Gear train 134, 192, 190,

3 i 122 may be arranged so as to rotate shaft 120 at a preselectedincreased speed; or the outside diameter of feed roll 40 may be madeslightly larger than the outside diameter of feed roll 41; or sprocket132 may be removed from shaft 130 and be attached to shaft 129 toinitially drive feed roll 4% with the gear train 134, 192, 190, 122arranged to drive feed roll 41 at a preselected relative speed to thespeed of feed roll 49.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the claims.

What is claimed is:

1. A longitudinal web stretching machine comprising, draw roll means,feed roll means, said draw and feed roll means being arranged to have acontinuous web pass there-between, means for rotating said draw and feedroll means to advance the web passing therebetween, and means forpivoting said draw roll means relative to said feed roll means tothereby vary the distance between said draw and feed roll means.

2. A longitudinal web stretching machine comprising draw roll means,feed roll means, said draw and said feed roll means being arranged tohave a continuous web pass thereabout, drive means for rotating saiddraw and said feed roll means to advance the web passing thereabout,speed adjusting means operably cooperatively with said drive means torotate said feed roll means at a different speed from said draw rollmeans, and means for pivoting said draw roll means relative to feed rollmeans to thereby very the distance between said draw and said feed rollmeans.

3. A longitudinal web stretching machine comprising draw roll means,feed roll means, said draw and said feed roll means being arranged tohave a continuous web pass thereabout, means for adjusting the distancebetween said draw and said feed roll means by pivoting said second drawroll means relative to said feed roll means, and stop means for limitingthe pivoting movement of said draw roll means.

4. A longitudinal web stretching machine comprising, draw roll means,feed roll means, said draw and said feed roll means being arranged tohave a web of temperature sensitive material pass thereabout, means forrotating said draw and said feed roll means, means for controlling thetemperature of said draw and said feed roll means to thereby control thetemperature of said web passing thereabout, and means for pivoting saiddraw roll means relative to said feed roll means to thereby vary thedistance between saiddraw and said feed roll means, said web beingstretchable as it advances between said feed and said draw roll meanswith temperature of the web being reduced by contact with said draw rollmeans.

5. A longitudinal web stretching machine comprising, draw roll means,feed roll means, said draw and said feed roll means being arranged tohave a web of temperature sensitive material pass thereabout, means forrotating said draw and said feed roll means, said draw roll meansrotating at a speed relatively faster than said feed roll means, meansfor introducing a heated fluid to said feed roll means to thereby heatsaid feed roll means, and means for pivoting said draw roll meansrelative to said feed roll means to thereby vary the distance betweensaid feed and said draw roll means, said web being stretchable as itpasses from said feed to said second draw roll means and heated by saidfeed roll means and cool set by said draw roll means.

6. A longitudinal web stretching machine comprising a frame, a set offeed rolls rotatably supported in said frame, pivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said-feed roller and said draw rollsindependently of each other and at different selected speeds, means forheating at least said set of feed rolls, control means for pivoting saidsecond set of draw rolls, a preselected distance from said set of feedrolls to thereby define a stretch zone for a web of material advancingfrom said set of feed rolls to said set of draw rolls, and pinch rollmeans to limit the slippage of saidweb as it is stretched in saidstretch zone.

7. A longitudinal web stretching machine comprising a frame, a set offeed rolls, rotatably supported in said frame, pivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said feed and said draw rolls independently ofeach other and at different selected speeds, means for heating at leastsaid feed rolls, control means for pivoting said draw rolls, apreselected distance from said feed rolls to thereby define a stretchzone for a web of material advancing from said feed rolls to said drawrolls, auxiliary heating means operable to heat said web as it advancesthrough said stretch zone, and pinch roll means to limit the slippage ofsaid stretch zone.

8. A longitudinal web stretching machine comprising, a frame, a set offeed rolls rotatably supported in said frame, pivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said set of feed and said set of draw rolls tothereby advance a thermoplastic web around said feed and draw rolls andthrough said machine, speed varying means associated with said drivemeans for rotating said set of draw rolls relatively faster then saidset of feed rolls, control means for pivoting said set of draw rolls apreselected distance from said set of feed rolls to thereby define astretch zone for the web advancing around said set of feed and set ofdraw rolls, fluid coupling means for introducing fluid into said set offeed and said set of draw rolls to thereby regulate the temperature ofeach of said sets of feed and draw rolls, at least said first set offeed rolls being heated to a temperature to heat soften said web wherebysaid web can be permanently stretched as it passes through said stretchzone under tension introduced by said set of draw rolls rotatingrelatively faster than said set of feed rolls, said set of draw rollsbeing at a temperature to cold set said heat softened web beyond thestretch zone and pinch roll means for limiting the slippage of said webas it is stretched in said stretch zone.

9. A longitudinal web stretching machine comprising a frame, a set offeed rolls rotatably supported in said frame, vpivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said set of feed and said set of draw rolls tothereby advance a theromoplastic web around said feed and draw rolls andthrough said machine, speed varying means associated with said drivemeans for rotating said set of draw rolls relatively faster than saidset of feed rolls, a linkage connected to said pivot means, across-shaft operably connected with said linkage, said cross-shaft beingrotatable for moving said linkage to pivot said set of draw rolls apreselected distancefrom said set of feed rolls to thereby define astretch zone for the web advancing around said set of feed and said setof draw rolls, a fiuid coupling for introducing a heating fluid intosaid set of feed rolls, said set of feed rolls being heated to atemperature to heat soften said Web whereby said Web can be permanentlystretched as it passes through said stretch zone under tensionintroduced as said set of draw rolls rotates faster than said set offeed rolls, a fluid coupling for introducing a fluid into said set ofdraw rolls, to temperature control said set of draw rolls and therebyset the web in said stretched condition.

10. The combination as set forth in claim 9, including auxiliary heatingmeans for heating said web as it passes through said stretch zone.

11. A longitudinal web stretching machine comprising, a feed and a drawroll means arranged to have a continuous web pass therebetween and tofurther provide a stretching zone for a web, means for pivotallyadjusting said draw roll means in relation to said feed roll means tovary the distance between said feed roll means and said draw roll meansand thereby provide a stretching zone for a web and the rate at which aweb may be stretched, means for introducing a heated fiuid to said feedroll means to thereby heat said feed roll means to heat soften a web,means for introducing a cooling fluid to said draw roll means to therebycool said draw roll means to set a Web, and means for rotating said feedroll means and said draw roll means at diiferent relative speeds toprovide a ratio of stretch for a web, the ratio at which a web may bestretched and the rate of stretch combining to vary the width of a webbetween said feed rolljmeans and said draw roll means.

12. The combination as set forth in claim 11, including auxiliaryheating means located in the stretching zone at said feed roll means foradding heat to a web.

13. A longitudinal web stretching machine comprising a frame, a set offeed rolls, ro-tatably supported in said frame, pivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said set of feed rolls and said set of drawrolls independently of each other and at different selected speeds,means for heating said set of feed rolls, control means for pivotingsaid set of draw rolls a pre-selected distance from said set of feedrolls to thereby define a stretch zone for a web of material advancingfrom said set of feed rolls to said set of draw rolls, auxiliary heatingmeans, and means for adjusting said auxiliary heating means to vary theposition of said auxiliary heating means toward and away from said setof feed rolls and to vary the position of said auxiliary heating meanswithin said stretch zone and thereby the intensity of said auxiliaryheating means upon a web of material advancing from said set of feedrolls to said set of draw rolls.

14. A longitudinal web stretching machine comprising a frame, a set offeed rolls rotatably supported in said frame, pivot means supported onsaid frame, a set of draw rolls rotatably mounted on said pivot means,drive means for rotating said set of feed rolls and said set of drawrolls to thereby advance a thermoplastic web around said feed and drawrolls and through said machine, speed varying means associated with saiddrive means for rotating said set of draw rolls relatively faster thansaid set of feed rolls, a linkage connected to said pivot means, across-shaft operably connected with said linkage, said cross-shaft beingrotatable for moving said linkage to pivot said set of feed rolls apreselected distance from said set of feed rolls to thereby define astretch zone for the web advancing around said set of feed rolls andsaid set of draw rolls, a fluid coupling for introducing a heating fluidinto said set of feed rolls, said set of feed rolls being heated to atemperature to heat soften said web whereby said web can be permanentlystretched as it passes through said stretch zone under tensionintroduced as said set of draw rolls rotates faster than said set offeed rolls, a fluid coupling for introducing a fluid into said set ofdraw rolls, to temperature control said set of draw rolls and therebyset the web in said stretched condition, and pinch roll means forlimiting the slippage of the web passing around said set of feed and setof draw rolls.

15. A longitudinal web stretching machine comprising a frame, a set ofcalender rolls rotatably supported in said frame, a pair of arms, meanspivoting said pair of arms to said frame, a second set of calender rollsrotatably mounted on said pair of arms, drive means for rotating saidfirst set of calender rolls and said second set of calender rollsindependently of each other and at different relative speeds to providea ratio of stretch for a web, a linkage, means connecting said linkageto said pair of arms, a cross shaft rotatably mounted in said frame, ahand wheel provided with graduations fixed to said cross shaft, anelongated square shaped member fixed to the said frame, a nut slidablymounted in said elongated square shaped member, a threaded shaftrotatably mounted in said square shaped nut, a first drive meansconnecting said cross shaft and said threaded shaft and a second drivemeans connecting said square Shaped nut and said linkage, wherebyrotations of said hand w-heel moves saidpai-r of arms about said meanspivoting said pair of arms to pivot said second set of calender rolls apreselected distance from said first set of calender rolls to therebydefine a stretch zone and the rate at which a web may be stretched.

16. A longitudinal web stretching machine comprising a frame, a set oftwo or more feed rolls rotatably supported in said frame, one of saidset of two or more feed rolls being termed a top roll, pivot meanssupported in said frame, a set of two or more draw rolls rotatablymounted on said pivot means, drive means for rotating said set of feedrolls and said set of draw rolls independently of each other and atdifferent selected speeds, means for heating said set of two or morefeed rolls, control means for pivoting said set of two or more drawrolls a pre-selected distance from said set of two or more feed rolls tothereby define a stretch zone for a web of material advancing from saidtop roll to said set of two or more draw rolls, and means for increasingthe surface speed of said top roll in relation to the rest of the feedrolls in said set of two or more feed rolls.

17. A longitudinal web stretching machine comprising a frame, a set oftwo feed rolls comprising a top roll and a companion roll rotatablysupported in said frame, pivot means supported in said frame, a set oftwo draw rolls rotatably mounted on said pivot means, drive means forrotating said set of feed rolls and said set of draw rolls independentlyof each other and at different selected speeds,vmeans for heating saidset of two feed rolls, means for pivoting said set of two draw rolls apreselected distance from said top roll to thereby define a stretch zonefor a Web of material advancing from said top roll to said set of twodraw rolls, the outside diameter of said top roll being larger than theoutside diameter of said companion roll to provide a relatively greatersurface speed between said top roll and said companion roll.

References Cited by the Examiner UNITED STATES PATENTS 2,547,736 3/1951Blake.

2,547,763 3/1951 Land et a1.

2,745,134 5/1956 Collins l81 2,895,165 7/1959 Fry 181 WILLIAM J.STEPHENSON, Primary Examiner.

1. A LONGITUDINAL WEB STRETCHING MACHINE COMPRISING, DRAW ROLL MEANS,FEED ROLL MEANS, SAID DRAW AND FEED ROLL MEANS BEING ARRANGED TO HAVE ACONTINUOUS WEB PASS THEREBETWEEN, MEANS FOR ROTATING SAID DRAW AND FEEDROLL MEANS TO ADVANCE THE WEB PASSING THEREBETWEEN, AND MEANS FORPIVOTING SAID DRAW ROLL MEANS RELATIVE TO SAID FEED ROLL MEANS TOTHEREBY VARY THE DISTANCE BETWEEN SAID DRAW AND FEED ROLL MEANS.